I think the CMake configure_file does not parse the correct information to the pkgconfig
cat lib/pkgconfig/libint2.pc
prefix=
exec_prefix=
libdir=
includedir=
Name:
Description: a library for the evaluation of molecular integrals of many-body operators over Gaussian functions
Version:
Libs: -L${libdir} -lint2
Cflags: -I${includedir} -I${includedir}/libint2
I think the CMake configure_file does not parse the correct information to the pkgconfig
cat lib/pkgconfig/libint2.pc